(svn r14463) -Fix [FS#2348]: small possible chance of desync due to sorting on pointer instead of by (station) index (PhilSophus)

2 files changed, 19 insertions, 1 deletions

diff --git a/src/oldpool.h b/src/oldpool.h
index d66a3a576..457e5327d 100644
--- a/src/oldpool.h
+++ b/src/oldpool.h
@@ -155,6 +155,23 @@ static void PoolCleanBlock(uint start_item, uint end_item)
 	}
 }
 
+/**
+ * Template providing a predicate to allow STL containers of
+ * pointers to pool items to be sorted by index.
+ */
+template <typename T>
+struct PoolItemIndexLess {
+	/**
+	 * The actual comparator.
+	 * @param lhs the left hand side of the comparison.
+	 * @param rhs the right hand side of the comparison.
+	 * @return true if lhs' index is less than rhs' index.
+	 */
+	bool operator()(const T *lhs, const T *rhs) const
+	{
+		return lhs->index < rhs->index;
+	}
+};
 
 /**
  * Generalization for all pool items that are saved in the savegame.
diff --git a/src/station_func.h b/src/station_func.h
index 5493f4e5a..12f045d15 100644
--- a/src/station_func.h
+++ b/src/station_func.h
@@ -7,6 +7,7 @@
 
 #include "station_type.h"
 #include "sprite.h"
+#include "oldpool.h"
 #include "rail_type.h"
 #include "road_type.h"
 #include "tile_type.h"
@@ -17,7 +18,7 @@
 void ModifyStationRatingAround(TileIndex tile, Owner owner, int amount, uint radius);
 
 /** A set of stations (\c const \c Station* ) */
-typedef std::set<Station*> StationSet;
+typedef std::set<Station*, PoolItemIndexLess<Station> > StationSet;
 
 StationSet FindStationsAroundIndustryTile(TileIndex tile, int w, int h);